Rock and Scroll

ROCK AND SCROLL


by Andrew Hunt





[I've corrected a couple of bugs that were in the original version. ]


[The subroutine at 65131 copied one too many bytes on each iteration,]


[causing the left-most column to get copied to the right-most column ]


[before the next column is scrolled in. ]


[The subroutine at 65180 copied one too many bytes when resetting the]


[attributes, overwriting the first byte of the printer buffer and so ]


[causing a crash if run on the 128K. ]


[I've done a corrected version in ROCKSCRL.TAP "RockSfix.o". JimG]





[NOTE: Enough space must be CLEARed below 65000 to make room for the ]


[messages. JimG]





I'm afraid your eyes don't deceive you: here's yet another message


scroller. "But why?" you cry. "We've been faithfully typing in Pitstop


scrollers for years, and we're up to our nostrils in the things. Our


eyes have developed a permanent list to the left from watching


messages scroll past. The last, the very last, thing we want right now


is another scroller. Take it away. Cast it thither."





But have patience, please. Andrew Hunt's scroller is different. Okay,


it's not that different, but it is remarkably short. It also scrolls


messages which are a whole screen high, exceedingly smoothly and in a


colour of your choosing. You can't say fairer than that.





Getting the thing up and running shouldn't take long. Just type in the


BASIC section and save it with SAVE "scroller" LINE 9999. Then turf


out a copy of the Hexloader from a previous YS and use it to enter the


hex section. Save that as "code". Then reload and run.





Most of the BASIC listing is taken up by a demo, and an explanation of


how it works. That saves me having to go through it all, as you should


be able to work out how to replace Mark's message with your own


without any trouble at all.